body, html{
  font-family: 'PingFang SC', 'STHeitiSC-Light', 'Helvetica-Light', Arial, sans-serif, 'Droid Sans Fallback';
  -webkit-tap-highlight-color: transparent;
  background: url("../images/bg.png") no-repeat;
  background-size: cover;
}
@media (-webkit-min-device-pixel-ratio: 2),(min-device-pixel-ratio: 2)
  body, html
    background-image: url("../images/bg@2x.png");
    background-size: cover;

@media (-webkit-min-device-pixel-ratio: 3),(min-device-pixel-ratio: 3)
  body, html
    background-image: url("../images/bg@3x.png");
    background-size: cover;
